Activation of inorganic gels



Feb. 26, F; |TTY JR 2,395,632

ACTIVATION OF INORGANIC GELS Filed April 28, 1943 FEED HOPPER -20 THERMOSTAT RELAY EXHAUST AIR HEATING Q \NSULATION ELEMENT -11 CLEANOUT-E CONTROL ll -1'0 PANEL Lg:

H TING CLEANOUT ELEMENT VIBRATING PAN 6 BYPASS Z2 BLOWER FINISHED PRODLE'T MR 0 FILTER {2 14 F Ik JLL 0 v gwuawhm 1- 2? 5. L zca %l 25 v VIBRATING Z2 PAN CONTROL W, %ujv HZ/ m Patented Feb. 26, l9

' ACTIVATION or moaoanrc ems Frederick Lucas Litty, lira, Baltimore, Md, as-

signor to The Davison emical Corporation, Baltimore, Md.

Application April 28, 1943, Serial No. 484,929

Claims;

This invention relates to the activationof silica and other oxide gels and more particularly has reference to an apparatus for the continuous activation of a gel.

Heretofore the activation of granular silica and other oxide gel was efiected by placing the material in trays which were subsequently placed in electric ovens and heated for extended periods of time ranging from 4 to 5 hours. The use of such apparatus necessarily required considerable handling of the gel and at most resulted in an intermittent process with its attendant disadvantages. I

An object of this invention is to provide an apparatus for activating silica and other oxide gels which will avoid the disadvantages of the prior art,

Another object of this invention is to provide an apparatus for continuously activating oxide" gels.

Still another object of this invention is to provide an apparatus for the activation of oxide gels including means for passing a dehydrating gas through a thin stream of the gel.

A further object of this. invention is to provide an apparatus having means to pass a thin stream of gel to be activated through a channel, means to pass a dehydrating gas transversely through (on. gi-ii) v the channel containing the gel and means for controlling the rate of flow of the gel through the channel in relation to the temperature of the gas after passing through the gel.

With these and other objects present invention in view, the comprises the parts and com-' binations hereinafter set forth andindicated in the accompanying drawing,

In the drawing:

Figure l is a somewhat diagrammatic vertical sectional view of an apparatus in which the present invention may be carried out,

Figure 2 is a detailed schematic view of the heat control circuits.

Figure 3 is a schematic view of thevibrating pain control circuit.

In carrying out the present invention, a stream 7 of the gel to be activated is passed downwardly through a vertical channel while a dehydrating activating gas is passed transversely through one or more portions of the stream. It has been found that an apparatus such as illustrated more or less diagrammatically in Figure 1 of the drawing is useful in the carrying out of the invention. This apparatus is comprised of a channel I which is formed by a pair of closely spacer foramlnous.

plates or screens 2. These screens areof such a width and so spaced that a channel of lon narrow cross section is provided between the same. The channel I is positioned substantially vertically within and extends through a chamber 3, through which heated air or other gas flows. As a matter of fact, the screens 2 forming the channel 6 serve as a partition dividing the chamher 3 into two substantially vertically extending compartments t and 9.

Chamber 3 is provided with an inlet t for the supply of a heated dehydrating activating gas and with an outlet ii for the discharge of the gas after having been passed in contact with the gel to be activated. In order to efiect an efficient multipass flow of the activating gas through the gel contained between the screens 2, a bafie t is positioned in compartment 9 and a second bade l is positioned in the other compartment 8 of chamber 5. The baifies t and l are staggered so that the flow of the gas from the inlet 6 will ss immediately through the lower portion of the channel 9 and be received in compartment e. The gas will then flow upwardly through compartment t, then transversely throughan intermediate portion of the channel 5 into compartv ment 9 above bafie 6. The gas upon reaching the upp r portion of compartment s will now upwardly and thence transversely through the up- I per portion of the. channel i into the portion oi compartment 8 above the bailie i from which the gas is discharged through the outlet 5.

Compartment t of chamber 3 communicates at its lower inlet end ti with a heating chamber it which contains a heating element ii, This heating element ma be an electric heating unit or any other type of heating device which will sufilce for the heating of air or other gas which flows through chamber l d to the inlet it.

Air or other suitable gas is drawn into a com duit 52 through a filter i3 and forced by'a blower it through a conduit to into the chamber to. A bt -oass connecting the intake conduit i2 and the discharge conduit it of the blower is provided with a valve it by means of which the flow of air or the pressure of air introduced into the chamher it can be regulated. The walls of the heating c amber to and of the chamber 3 through which he channel i extends are of double thickness as illustrated in the drawing with insulating material positioned between the double walls. This serves to minimize the heat losses from the apparatus.

At the bottom of the compartment 8 anddirectly above the bafiles' 5 and i, there are provided clean-out openings from which any accumulation of finely divided gel can be removed to provide for the free flow of the activating g s through the stream of gel contained in the channel I.

The heating element is preferably thermostatically controlled by a thermostat H which in the case of an electric heating element may be incorporated in a circuit such as diagrammatically illustrated in Figure 2 of the drawing. In the case of an electric heating element, the thermostat l1 controls a relay' l8 which in turn regulates the supply of current from the supply line l9 to the heating element ii. If a steam heating element is employed, the thermostatwould control the operation of an electrically actuated steam regulating valve. Thus, regardless of the type of heating element used, thermostat ll positioned at the inlet 4 serves to insure a supply of activating gas at a predetermined temperature for effecting the activation of the gel.

The gel to be activated is supplied to the channel l by a feed hopper which communicates with the upper end of the channel I. Flow of the gel through thechannel l is controlled by a vibrating pan apparatus which comprises a pan 2| positioned directly beneath the discharge end of the channel I. This pan is positioned close enough to the lower end of the channel I to permit the discharge of a given amount of material from the channel after which the. discharge will be stopped until the material collected in the pan 2| is removed therefrom. By constantly vibrating the pan 2|, the gel will be discharged from the pan as illustrated in Figure 1 of the drawing at a rate depending upon the amplitude and/or frequency of the vibrations imparted to the pan. Obviously, the rate of discharge from the lower end of the channel I will be equal to the rate of discharge from the pan 2|.

An electrically controlled vibrator. is associated with the pan 2| and as illustrated in Figure 3 of the drawing the electrical control means 22 for the vibrating pan is associated with thermostats 23 and 24, either or both of which control the operation of the vibrating pan to regulate the rate of discharge of the gel therefrom. Thermostat 23 is positioned in compartment 8 below the bailie I and thermostat 24 is positioned in the upper portion of compartment 8 near the outlet 5. With this arrangement the rate of flow of the gel to be activated through the channel l is controlled at such a rate that the temperature of the activating gas will be sufliciently high throughout its travel in contact with the gel to insure an effective activation of the gel.

' In' addition to the thermostats I1, 23 and 24,

temperature indicating elements 25, 2B, 21 and 28 are positioned as illustrated in Figure 1 throughout the flow path of the activating gas to indicate the temperature of the gas at its various stages throughout its flow path.

A plurality of pressure responsive devices 29, 30 and 3| may also be positioned at difierent stagesthroughout the flow path of the activating gas to indicate the various pressures of the gas at these stages.

It has been found that by activating a gel in accordance with the present invention and controlling the heating of the activating gas to supply gas at a substantially constant temperature and by controlling the flow of the gel to be activated through the channel in accordance with the temperature of the gas after having passed in contact with the gel, an effective activation of the gel can be obtained.

From the foregoing description, it will be apreciated that the present invention provides an apparatus for the continuous activation of an inorganic gel which, due to the automatic control of the temperature of the activating as and the rate of feed of the gel in contact with the gas, will insure the production of a product of uniform quality.

I claim:

1. An apparatus for eifecting the continuous activation of an oxide gel comprising a vertical channel formed ofa pair of closely spaced foraminous walls, means joining the adjacent lateral edges of said walls, means for supplying the channel with gel, means for adJusting the discharge of gel from the bottom of the channel, means for passing a drying gas transversely through the foraminous walls of the channel and the gel therein, means for heating said gas before it contacts the gel, means responsive to the temperature of the gas before contacting the gel for. controlling the heatingmeans, and means responsive to the temperature of the gas after passing through the gel for controlling the discharge adjusting means.

2. An apparatus for effecting the continuous activation of an oxide gel comprising a substantially vertical duct having a gas inlet at the lower portion thereof and an outlet at the upper region thereof, a pair of substantially vertical closely spaced ioraminous walls providing a channel therebetween dividing said duct into two substantially vertical passages, baiile means extending between the foraminous walls and the adjacentwalls of the duct intermediate the upper and lower portions of saidduct to provide a tortuous gas flow responsive means in said tortuous path near the end thereof for controlling the regulating means.

3. An apparatus for eifecting the .continuous activation of an oxide gel comprising a substantially vertical duct having a gas inlet at the lower portion thereof and an outlet at the upper region thereof, a pair of substantially vertical closely .spaced foraminous walls providing a channel therebetween dividing said duct into two substantially vertical passages, bailie means extending between the foraminous walls and the adjacent walls of the duct intermediate the upper and lower portion of said duct to provide a tortuous gas flow path from the inlet into one passage and then through the foraminous walls into the other passage, means for introducing a heated gas into said inlet, means for supplying gel to be activated to the upper portion of said channel, a vibrating pan associated with the lower end of said channel for regulating the discharge of granular gel from the lower end of said channel and heat responsive devices spaced at intervals in said path to control the rate of vibration of said pan.

4. An apparatus for effecting the continuous activation of an oxide gel comprising a substantially vertical duct having a gas inlet at the lower portion thereof and an outlet at the upper region thereof, a pair of substantially vertical closely spaced foraminous walls providing a channel therebetween dividing said duct into two substanaaeaesa tially vertical passages, baflle mean extending between the foramincus walls and the adjacent walls of the duct intermediate the upper and lower portions of said duct to provide a tortuous gas flow path from the inlet into ne passage and then through the foraminous walls into the other passage, means for introducing a heated gas into said inlet, means for supplying gel to be activated to the upper portion of said channel, means for regulating the discharge of granular gel from the lower portion of said channel, and means, positioned at a plurality of regions in said path, responsive tothe temperature of the gas after passing through the foraminous walls for controllin the operation of the granular gel discharge regulating means.

5. An apparatus for effecting the continuous activation of an oxide gel comprising a substantially vertical duct having a gasinlet at the lower portion thereof and an'outlet at the upper region thereof, a pair of substantially vertical closely spaced foraminous walls providing a channel i for introducing a gas therebetween dividing said duct into two substantially vertical passages, baflle means extending between the foraminous walls and the adjacent walls of the duct intermediate the upper and lower portions of said duct to provide a tortuous gas flow path from the inlet into one passage, then through one portion of the foraminous walls into the other passage, back through another portion of the forarninous walls into the first passage and finally again through another portion of th foraminous walls, a gas heating chamber communicating with said inlet, heating means in said chamber, means under pressure into said chamber, means for supplying granular gel to be activated to said channel, means for regulating the discharge of gel from the lower portion of said channel, and means responsive to the temperature of the gas after passage through the tortuous path and the gel in. the channel for controlling the dis= charge regulating means.

FREDERICK muons arm JR. 

